This invention relates to devices for rotating a polygonal fastener, such as a bolt head, nut or the like. The new device has an open-end wrench structure with a movable jaw, ratchet control apparatus.
Fixed jaw, open-end wrenches known in the art may be limited in use for rotating polygonal fasteners because of a long swing or rotational movement requirement. For example, for a hexagonal headed bolt the wrench arm must be rotated 60 degrees to reposition the wrench on adjacent faces of the bolt head to continue to rotate the bolt. This may prevent use of the wrench in areas with limited space. Also, repositioning the wrench for each stroke may add time and effort to manipulating the fastener. Closed-ring configured wrenches allow smaller swing angles, but may still have to be repositioned, or if a socket-type ratchet, may not be used on hydraulic lines, fuel lines, fasteners with long shafts and the like due to vertical clearance requirements.
There may be various devices and inventions known that have been developed in attempts to produce a strong, compact open-end ratcheting wrench. The general approaches for such devices may include: a wrench with fixed jaws that have a special shape that applies torque in one direction and slips around the fastener in an opposite direction; a wrench with both jaws integral with the handle, having small pawls, rollers or camming components carried around their internal surfaces to allow gripping movement of a fastener in only one direction; and open-end wrenches with one or both jaws unidirectionally relieving to allow ratcheting. The first type of mechanism only allows large rotational or swing angle use, that is, for a hexagonal bolt head the swing angle would be 60 degrees. The second type of wrench may be inherently fragile and complicated to manufacture and assemble.
The third type of open-end ratcheting wrenches, those that use a relieving jaw, may have failed to achieve both adequate strength and a compact profile. Several designs may utilize a movable jaw that may be slidably positioned over a wrench head with an attached fixed jaw and may be fastened by a pin to allow rotation of the movable jaw. This may result in a weak mechanism with a bulky head. Another design that has a movable jaw slidably positioned over a wrench head or handle with curved surfaces for engagement when torquing a fastener is also fastened by a pin positioned in a slot. This design appears to also result in a weak mechanism resulting in breakage of the jaw mechanism as experienced by users.